Solid dextrose is conventionally manufactured by crystallizing supersaturated, high dextrose syrups and recovering the crystals therefrom in .alpha.-D-dextrose monohydrate crystal form (e.g., see U.S. Pat. No. 3,039,935). Yields depend upon carefully controlled cooling temperatures and dextrose supersaturation conditions. Complete recovery of the solids from the dextrose syrup cannot be accomplished because effective dextrose crystallization and separation therefrom requires supersaturated dextrose solutions. Accordingly, a significant portion of the dextrose will remain in the mother liquor or syrup upon completion of the dextrose crystallization step. Anhydrous .alpha.-dextrose is generally manufactured by dissolving .alpha.-D-dextrose monohydrate crystals in water and crystallizing at temperatures of 60.degree.-65.degree. C. in vacuum pans under carefully controlled processing conditions.
Solidification of all the conversion syrup solids without separating the dextrose therefrom has been proposed. U.S. Pat. No. 3,197,338, by T. L. Hurst, discloses a process for producing a crystalline, non-caking, dextrose product. In Hurst et al., a refined dextrose conversion syrup is concentrated to at least 95% solids (preferably greater than 98% solids), crystallized by kneading (e.g., at 170.degree. F.-230.degree. F.) and extruded in the form of ribbon or strand into a zone which rapidly cools the product to less than 150.degree. F. The extrudate is then granulated to appropriate particle size. In U.S. Pat. No. 3,236,687, dextrose conversion syrup solids are reportedly converted into a solid form by subjecting a syrup concentrate (e.g., at a 93-96% solids level and 180.degree.-220.degree. F.) to high shear in the presence of gas to form minute glucose crystals. The nucleated, creamy, frothy dextrose mass is deposited upon a moving belt and solidified in a series of cooling zones maintained at progressively lower temperatures (e.g., first zone at 180.degree.-220.degree. F., second zone at 140.degree.-180.degree. F. and third zone less than 100.degree. F.). The solidified mass is chipped, conditioned for 2-3 hours at 120.degree.-180.degree. F., ground and redried. Japanese Patent Specification Nos. 26250/61 and 23995/63 also disclose processes which rely upon aeration to convert dextrose conversion syrups to crystalline dextrose. Although numerous processes for directly converting dextrose conversion syrups into solids have been proposed, the dextrose monohydrate crystallization and separation process remains essentially the exclusive source of dextrose solids in this country.
Applicants sought a more effective, alternative method to produce a solid dextrose product on a commercial scale. They desired to produce a product having many of the desired attributes of crystalline dextrose monohydrate (e.g., free-flowing, non-compacting, stability against physical and chemical degradation such as typically encountered in the shipment and the trade usages thereof, adequate solubility and dispersibility in aqueous systems, appropriate whiteness and sweetness without off-flavors, etc.). A solid dextrose possessing uniquely different properties and usefulness was sought. A solid dextrose product which could be used in many applications as replacement for sucrose and/or dextrose monohydrate was also desired.